Receptor Plants Alleviated Allelopathic Stress from Invasive Chenopodium ambrosioides L. by Upregulating the Production and Autophagy of Their Root Border Cells.

Chenopodium ambrosioides L. is an invasive plant native to the Neotropics that has seriously threatened the ecological security of China, and allelopathy is one of the mechanisms underlying its successful invasion. Maize (Zea mays L.) and soybean (Glycine max (L.) Merr.), as the main food crops, are usually affected by C. ambrosioides in their planting areas. The purpose of this study was to investigate the ultrastructure, autophagy, and release-related gene expression of receptor plant root border cells (RBCs) after exposure to volatile oil from C. ambrosioides and its main component α-terpene, which were studied using maize and soybean as receptor plants. The volatiles inhibited root growth and promoted a brief increase in the number of RBCs. As the volatile concentration increased, the organelles in RBCs were gradually destroyed, and intracellular autophagosomes were produced and continuously increased in number. Transcriptomic analysis revealed that genes involved in the synthesis of the plasma membrane and cell wall components in receptor root cells were significantly up-regulated, particularly those related to cell wall polysaccharide synthesis. Meanwhile, polygalacturonase and pectin methylesterases (PME) exhibited up-regulated expression, and PME activity also increased. The contribution of α-terpene to this allelopathic effect of C. ambrosioides volatile oil exceeded 70%. Based on these results, receptor plant root tips may increase the synthesis of cell wall substances while degrading the intercellular layer, accelerating the generation and release of RBCs. Meanwhile, their cells survived through autophagy of RBCs, indicating the key role of RBCs in alleviating allelopathic stress from C. ambrosioides volatiles.

The competitive strategies of poisonous weeds Elsholtzia densa Benth. on the Qinghai Tibet Plateau: Allelopathy and improving soil environment.

Introduction: The competitive strategies of plants play a crucial role in their growth. Allelopathy is one of the weapons that plants use to improve their competitive advantage. Methods: In order to explore the competitive strategy of a poisonous weed Elsholtzia densa Benth. (E. densa) on the Qinghai-Tibet Plateau (QTP), the effects of decomposing substances of E. densa on growth, root border cells (RBCs) characteristics of highland crop highland barley (Hordeum vulgare L.), and soil environment were determined. Results: The decomposing allelopathic effect of E. densa on the germination and seedling growth of highland barley mainly occurred in the early stage of decomposing. The allelopathic effects were mainly on seed germination and root growth of highland barley. After treatment with its decomposing solution, the RBC's mucilage layer of highland barley thickened, and the RBC's activity decreased or even apoptosis compared with the control. However, only the above-ground part of the treatment group showed a significant difference. The effects of E. densa decomposed substances on the soil environment were evaluated from soil physicochemical properties and bacterial community. The results showed that soil bacteria varied greatly in the early stage of decomposion under different concentrations of E. densa. In addition, E. densa decomposing substances increased the soil nutrient content, extracellular enzyme activities, and bacterial community diversity. In the process of decomposition, the bacterial community structure changed constantly, but Actinobacteriota was always the dominant phylum. Discussion: These results indicated that E. densa might adopt the following two strategies to help it gain an advantage in the competition: 1. Release allelochemicals that interfere with the defense function of surrounding plants and directly inhibit the growth and development of surrounding plants. 2. By changing the physical and chemical properties of soil and extracellular enzyme activity, residual plant decomposition can stimulate soil microbial activity, improve soil nutrition status, and create a more suitable soil environment for growth.

Cytotoxic Effect of the Essential oils from Erigeron Canadensis L. on Human Cervical Cancer HeLa Cells in Vitro.

Erigeron Canadensis L. (E. canadensis) is a widely distributed invasive weed species in China. Potentially anti-cancer qualities may exist in its essential oils (EOs). The purpose of this study was to analyze the components of the EOs of E. canadensis and their effects on the normal liver cell lines L02 and the human cervical cancer cell lines HeLa. The EOs from the upper region of E. canadensis were prepared, its components were identified by GC/MS. Cell viability, cell morphology observation, AO/EB dual fluorescence staining assay, flow cytometry, mitochondrial membrane potential, western blot, caspase inhibitor test, and oxidative stress tests were used to investigate the impact of the EOs on HeLa cells. Network pharmacological analysis was employed to study the potential mechanism of the EOs in the treatment of cervical cancer. According to the findings, the EOs had 21 chemical components, of which limonene made up 65.68 %. After being exposed to the EOs, the cell viability of HeLa and L02 dramatically declined. The inhibition of EOs was more effective than that of limonene when used in an amount equivalent to that in the EOs. L02 cells were less susceptible to the cytotoxicity of EOs than HeLa cells were. Furthermore, EOs altered the cell cycle in HeLa cells and caused oxidative stress and apoptosis. Compared with the control group, the reactive oxygen species (ROS) levels increased in HeLa cells at first and then decreased, total superoxide dismutase (SOD) and catalase (CAT) activities in HeLa cells significantly decreased. G1 phase cells decreased whereas G2/M phase cells increased. The rate of apoptosis rose. Reduced mitochondrial membrane potential and Caspase-3, -9, and -12 protein expression were both observed. Nerolidol, dextroparaffinone, and α-pinene were shown to be the primary components for the suppression of HeLa cells, according to the results of the prediction of pharmacologic targets. In conclusion, findings of this study indicated the EOs may have the potential to curb the growth of cervical cancer cells. Further research is needed to explore the in vivo effect of EOs.

Methylmercury cytotoxicity and possible mechanisms in human trophoblastic HTR-8/SVneo cells.

Methylmercury (MeHg) exposure during pregnancy can lead to adverse outcomes, including miscarriage and intrauterine growth retardation. In this study, MeHg cytotoxicity and its mechanisms in HTR-8/SVneo cells were investigated. MeHg inhibited HTR-8/SVneo cell viability and severely disrupted the cellular submicrostructure, showing a time-dose effect relationship. After MeHg treatment, the reactive oxygen species levels, malondialdehyde content, and superoxide dismutase (SOD) and catalase activities in the HTR-8/SVneo cells increased significantly with increased MeHg concentration (P<0.05). Similarly, MeHg also induced HTR-8/SVneo cell apoptosis in a dose-dependent manner. The proportion of cells in G1 phase decreased with increasing MeHg concentration, while that in the S and G2/M phases gradually increased. Moreover, cell migration and invasion capacities gradually decreased with increasing MeHg concentration, showing a significant difference between the MeHg-treated and control groups. Genes related to oxidative stress (HSPA6, HSPA1A, Nrf2, SOD1, HO-1, NQO1, OSGIN1, and gPX1), cell cycle (P21 and CDC25A), apoptosis (CYCS and AIFM2), and migration and invasion (CXCL8, CXCL3, CLU, IL24, COL3A1, MAPT, and ITGA7) were differentially expressed in the MeHg-treated group, indicating MeHg toxicity and mechanism of action. This study will provide insights into the prevention and treatment of pregnancy-related diseases caused by MeHg.

[Essential Oil of Chenopodium ambrosioides Induced Caspase-Dependent Apoptosis in SMMC-7721 Cells].

Objective: To investigate the inhibition of cell proliferation by essential oil of Chenopodium ambrosioides on the human liver cancer SMMC-7721 cells and human liver LO2 cells,and to study the mechanism of anti-tumor in vitro. Methods: The inhibition of cell proliferation by essential oil of Chenopodium ambrosioides was determined by MTT assay; the distribution of cell cycle was analyzed by flow cytometry( FCM) with PI staining; cell morphology and apoptosis effect of SMMC-7721 cells were observed by microscope; the apoptotic rate was quantified by FCM with Annexin V / PI double staining. Results: Essential oil of Chenopodium ambrosioides could significantly inhibit the cell proliferation in a concentration-time-dependent manner( P < 0. 05),and the IC50 values on SMMC-7721 cells were lower than human liver LO2 cells at 24,48 and 72 h,respectively( P < 0. 05); cell cycle of SMMC-7721 cells was arrested in G0/G1phase; morphological observation revealed that the cells were wrinkled and the cellular cohesiveness of cells was reduced; nuclear was condensed and in orange colour,of which were the late apoptotic features; and the apoptotic rate increased in a concentration-dependent manner( P < 0. 05),non-viable apoptotic rate was obviously decreased with caspase inhibitor in 100 µg / m L essential oil of Chenopodium ambrosioides( P < 0. 01). Conclusion: Essential oil of Chenopodium ambrosioides can inhibit SMMC-7721 cell proliferation, which may be related to inducing cell cycle arrest and caspase-dependent apoptosis.

[Isolation, Identification and Characteristic Analysis of an Oil-producing Chlorella sp. Tolerant to High-strength Anaerobic Digestion Effluent].

A Chlorella strain tolerant to high-strength anaerobic digestion effluent was isolated from the anaerobic digestion effluent with a long-term exposure to air. The strain was identified as a Chlorella by morphological and molecular biological methods, and named Chlorella sp. BWY-1, The anaerobic digestion effluent used in this study was from a biogas plant with the raw materials of swine wastewater after solid-liquid separation. The Chlorella regularis (FACHB-729) was used as the control strain. The comparative study showed that Chlorella sp, BWY-Ihad relatively higher growth rate, biomass accumulation capacity and pollutants removal rate in BG11. and different concentrations of anaerobic digestion effluent. Chlorella sp. BWY-1 had the highest growth rate and biomass productivity (324.40 mg.L-1) in BG11, but its lipid productivity and lipid content increased with the increase of anaerobic digestion effluent concentration, In undiluted anaerobic digestion effluent, the lipid productivity and lipid content of Chlorella sp. BWY-1 were up to 44. 43% and 108. 70 mg.L-1, respectively. Those results showed that the isolated algal strain bad some potential applications in livestock wastewater treatment and bioenergy production, it could be combined with a solid-liquid separation, anaerobic fermentation and other techniques for processing livestock wastewater and producing biodiesel.

Carbon and energy fixation of great duckweed Spirodela polyrhiza growing in swine wastewater.

The ability to fix carbon and energy in swine wastewater of duckweeds was investigated using Spirodela polyrhiza as the model species. Cultures of S. polyrhiza were grown in dilutions of both original swine wastewater (OSW) and anaerobic digestion effluent (ADE) based on total ammonia nitrogen (TAN). Results showed that elevated concentrations of TAN caused decreased growth, carbon fixation, and energy production rates, particularly just after the first rise in two types of swine wastewater. Also, OSW was more suitable for S. polyrhiza cultivation than ADE. Maximum carbon and energy fixation were achieved at OSW-TAN concentrations of 12.08 and 13.07 mg L(-1), respectively. Photosynthetic activity of S. polyrhiza could be inhibited by both nutrient stress (in high-concentration wastewater) and nutrient limitation (in low-concentration wastewater), affecting its growth and ability for carbon-energy fixation.

Effects of high ammonium level on biomass accumulation of common duckweed Lemna minor L.

Growing common duckweed Lemna minor L. in diluted livestock wastewater is an alternative option for pollutants removal and consequently the accumulated duckweed biomass can be used for bioenergy production. However, the biomass accumulation can be inhibited by high level of ammonium (NH4 (+)) in non-diluted livestock wastewater and the mechanism of ammonium inhibition is not fully understood. In this study, the effect of high concentration of NH4 (+) on L. minor biomass accumulation was investigated using NH4 (+) as sole source of nitrogen (N). NH4 (+)-induced toxicity symptoms were observed when L. minor was exposed to high concentrations of ammonium nitrogen (NH4 (+)-N) after a 7-day cultivation. L. minor exposed to the NH4 (+)-N concentration of 840 mg l(-1) exhibited reduced relative growth rate, contents of carbon (C) and photosynthetic pigments, and C/N ratio. Ammonium irons were inhibitory to the synthesis of photosynthetic pigments and caused C/N imbalance in L. minor. These symptoms could further cause premature senescence of the fronds, and restrain their reproduction, growth and biomass accumulation. L. minor could grow at NH4 (+)-N concentrations of 7-84 mg l(-1) and the optimal NH4 (+)-N concentration was 28 mg l(-1).

[Oxidative damage of volatile oil from Chenopodium ambrosioides on Vicia faba root tip cells].

Chenopodium ambrosioides is an invasive species, which has strong allelopathic effect on surrounding plants. In this study, the methods of soil culture and filter paper culture were adopted to simulate the eluviation and volatilization of the volatile oil from C. ambrosioides, respectively, and to investigate the allelopathy of the volatile oil on the lipid peroxidation and antioxidant enzyme activities of Vicia faba root tip cells, with the mechanisms of the induced tip cell apoptosis analyzed. At the early stage (24 h) of soil culture and filter paper culture, the superoxide dismutase, peroxidase and catalase activities of the tip cells decreased after an initial increase with the increasing dose of the volatile oil, and the malondialdehyde content of the tip cells increased with the increasing volatile oil dose and treated time. At the midterm (48 h) and later (72 h) stages of soil culture and filter paper culture, a typical DNA ladder strip appeared, suggesting that the volatile oil from C. ambrosioides could induce the apoptosis of the tip cells, and the apoptosis was dose- and time dependent. This study showed that the volatile oil from C. ambrosioides could act on its surrounding plants via eluviation and volatilization, making the lipid peroxidation of acceptor plants aggravated and the antioxidant enzyme activities of the plants inhibited, resulting in the oxidative damage and apoptosis of the plant root tip cells, and accordingly, the inhibition of the plant growth. Under soil culture, the root tip cells of V. faba had higher antioxidant enzyme activities and lesser DNA damage, suggesting that the volatile oil from C. ambrosioides via volatilization had stronger allelopathy on the growth of surrounding plants than via eluviation.

[Studies on chromosomes preparation and karyotype analysis of Phellodendron chinense].

The article reported method of making chromosomes by callus and used in karyotype analysis of Phellodendron chinense. The results demonstrated that the chromosme amount to 80. The karyotype formula is K(2N) =80 =68m(2SAT) +6sm +6T. 34 pairs are metacentric (m), 3 pairs are submetacentric (sm) and 3 pair are terminal point (T). Two small satellites were observed on the short arms of the third pair.